Microwave runs (light and turntable on) but food remains cold; E003 appears on the display after a short time.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Critical safety warning: The high-voltage section of a microwave can be lethal. Do not attempt to service the magnetron, transformer, capacitor, or HV diode unless you are properly trained and equipped to safely discharge the capacitor.
User-level checks:
- Confirm that you are using a microwave-safe container and that the load is not too small (e.g., always heat at least 200 ml of water).
- Reset the appliance by unplugging for 5 minutes, then reconnect and test again.
Technician-level checks:
- Remove the cabinet and visually inspect the high-voltage fuse (often in a plastic holder near the transformer). Replace only with the exact same rating if blown.
- Check the high-voltage diode for short or open using a multimeter with diode test (after safely discharging the capacitor).
- Inspect the magnetron for burn marks, cracked ceramic insulators, or a burnt smell. Replace if damaged.
- Measure primary and secondary windings of the HV transformer for continuity and correct resistance.
If you are not experienced with high-voltage electronics, do not proceed beyond basic checks. Contact a Neff service center to replace the magnetron or high-voltage components.